Various technologies have been developed to enable hard-of-hearing individuals communicate using telephone communication systems. For example, text telephones, such as Telecommunication Devices for the Deaf (TDD), enable deaf, hard of hearing, speech-impaired individuals to communicate over the telephone with hearing and speaking parties using conventional telephones. In TDD systems, the hard-of-hearing person typically uses a telephone teletype keyboard or TTY, a specially equipped device with a keyboard, to type messages and a text display for presenting responses to the caller.
Telecommunication relay services or dual-party relay services enable deaf, hard of hearing, speech-impaired individuals to employ text telephones for engaging in a communication session over a telephone network with a person who has a conventional voice telephone. Relay services involve a hard-of-hearing individual using a keyboard to communicate and a display device to understand what is being said by the other party. The hearing person hears what is being said and uses his voice to communicate. A relay communication assistant (CA) acts as the interface in this situation. The CA relays information from one communication protocol to another. For example, the CA types what the hearing person says and sends the text to the hard-of-hearing person. The CA can also read aloud text messages from the hard-of-hearing person so that the hearing person can hear the message.